my plan power wise is to have a power inverter connected to a source that powers on when the car turn on, and have it so that when the laptop loses power and switches to battery power it goes to hibernate mode and just runs that off the battery, when the car turns on, tap the screen and it wakes up. As far as placement goes, I was thinking glovebox or under driver seat. I was thinking trunk but then I'd have to run a usb cable and vga cable and I'm worried about signal loss that way.

Sounds like you have a solid plan, although I recommend using a DC-DC power setup over an inverter any day of the week.
A car adapter for your laptop would achieve the same thing and not bring about the potential of excess heat, ineffeciency and postential noise in the audio setup.

the signal loss from the trunk shouldn't be too much of a problem altough usb stuff can sometimes act up over 10', there are usb extenders though that boost that limit. the touchscreen wakey thing sounds good but you have to test it, not to sure how reliable that may be if it even works at all.

one advantage you'd have with the dock is you can hack into the power switch on it if it has one & have a hardware startup solution over a software one, which should be much more reliable & trouble free

also, I second about dc/dc power supply, much cleaner power & more efficient.

Heat may be an issue in a trunk (sun on the flat surface can be brutal) unless you could give it its own insulated housing. Many trunks (and my van's side panel) have ventilation exhaust. I'm going to add a 12V PC fan to mine so the laptop will stay cooler.

Well I tested my wake by touching screen trick and it didn't work so I soldered on a button connected to some speaker wire that I'll extent to my dash. The trunk is sounding like a better option, now here's my new problem. I created a Hibernate shortcut using the directory rundll32.exe PowrProf.dll, SetSuspendStat Hibernate and when I click on it it goes to hibernate, but I can't figure out how to make this shortcut an application in Roadrunner, what I have in the ini is
[GENERAL]
PATH = C:\Program Files\Road Runner\LAUNCH\Hibernate\Hibernate.exe
TryEmbeddedTimeOut = 5
WindowSearchString=hibernate

the most common way is to have the laptop hibernate when on battery power for X amount of minutes, that is, if your retaining the laptop battery...

also, if your going to use a startup shutdown controller this can be automatic by setting the power button to hibernate when pressed, then even if your not going to use a controller for this, you can still tap the same button you use to start it by the same method.

ya, i tried the timer, but winamp/roadrunner kept it from going. I thought of a new solution though, I just made the poewr button make it go to hibernate mode since Its already going to the dash anyways to take it out of hibernate mode.